You can never go wrong with a white tee, jeans and a great pair of flats! (atelierdore.com)
Little makeup (or none at all), a tank top or two, a great pair of flats (flip flops would make it even simpler), and a scarf to tie it all together. (wildruffle.com)
Get a color / print you really love and you will be able to dress up the outfit with a cardigan and a great pair of flats or wedges for a more formal setting. (inexpensivematernityclothes.org)